Simulation of commercial fixed-bed reactor for maleic anhydride synthesis: application of different kinetic models and industrial process data

In this study, we have developed a relatively simple mathematical model capable of both simulating the synthesis of maleic anhydride from n-butane in industrial fixed-bed reactor and determining the influences of inlet process parameters on reactor performance. Ten kinetic models were used, and each of them was used in combination with a simplified reactor model. The validation of the developed mathematical model was performed using three process data sets with five process parameters obtained from industrial fixed-bed reactor. The simulation results showed a good agreement with the measured values for three kinetic models. The most influential inlet process parameters are inlet flow rates of n-butane and oxygen. The maleic anhydride yield is more sensitive to the changes of inlet process parameters than n-butane conversion and maleic anhydride selectivity. By increasing the inlet molar flow of n-butane for 20%, n-butane conversion and maleic anhydride yield are decreased for 3.3% and 5.0%, while maleic anhydride selectivity is increased for 6.7%. In order to increase the selectivity of maleic anhydride, it is necessary to decrease the inlet temperature of reaction mixture, the inlet pressure of reaction mixture as well as the inlet molar flow of oxygen, and to increase the inlet molar flow of n-butane.